Ask the Expert from Channel4.com

Stem Cells – Your Questions & Answers

Here are the questions that you asked about stem cells and genetic research... and Robin Lovell-Badge's answers.

Q1: My son has recently been diagnosed with Muscular Dystrophy. Is there any hope that stem cell research could find a cure for this terrible genetic disorder?

Q2: How do stem cells cure cancer?

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Q1: My son has recently been diagnosed with Muscular Dystrophy. Is there any hope that stem cell research could find a cure for this terrible genetic disorder?
Trevor Broadhurst, Hamilton

Robin Lovell-Badge: I am very sorry to hear that your son has Muscular Dystrophy. It is a terrible disease, and because of this there are many very capable scientists and clinicians working to find ways of ameliorating its effects or even to find cures. Many approaches are being pursued, from pharmaceuticals to gene therapy, but it is indeed a disorder that lends itself to stem cell based treatments.

Muscles contain a resident population of stem cells. These are termed "satellite cells" because they are small cells (with a single nucleus) located next to the much larger muscle fibre cells. In most individuals these satellite cells are able to repair muscles and to regenerate muscle cells lost through normal processes of wear and tear. They are also responsible for rebuilding muscles even after quite significant accidental damage. However, their regenerative capacity is not unlimited and they become exhausted in patients suffering conditions like Muscular Dystrophy.

So scientists are exploring ways of growing satellite cells in the lab in sufficient numbers and in such a way that they can be transplanted back into muscle to help with its repair. However, because Muscular Dystrophy patients tend to run out of satellite cells, we have to find alternative sources and this type of research is occupying many stem cell biologists.

In theory, the satellite cells could be obtained from another person with a close genetic match so that they would not be rejected by the patient’s immune system (a problem with many types of transplant). However, apart from a donor willing to give some muscle, this would require a reliable way of isolating and growing sufficient numbers of satellite cells, which is still a problem. In contrast, Embryonic Stem Cells, which are derived from very early embryos can be grown in very large numbers. Indeed, we have found ways to obtain muscle cells from Embryonic Stem Cells specifically with the intention of developing treatments for Muscular Dystrophy. Currently, most Human Embryonic Stem Cell lines are made from spare embryos left over after in vitro fertilisation, so unless there are still be concerns about having an appropriate tissue match for transplants.

It would be useful to be able to obtain such cell lines from the patient by nuclear transfer methods, so-called "therapeutic cloning", but no one has yet derived human Embryonic Stem Cells in this way.

Finally, it might be possible to use another type of adult stem cell taken from the patient, one that can also be coaxed to give rise to muscle in certain circumstances. Very promising research is exploring the use of blood vessel associated stem cells termed "mesoangioblasts", which can be grown in the lab and give rise to several cell types including muscle.

It is likely that stem cell based methods will be combined with other treatments that help reduce inflammation and allow satellite cells to survive better. Moreover, any approach that uses cells derived from the patient will probably require the original gene defect to be corrected, and in recent years several ways of carrying out such gene therapy have proved quiet promising.

So there is a lot of hope that methods being developed now will provide cures in the future. But I must stress that it takes a long time to find out whether any new treatment will be both safe and beneficial in humans.

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